A comparative study of effective core potential and full‐electron calculations in Mo compounds. I. An analysis of topological properties of bond charge distribution

Abstract

Abstract Effective core potential (ECP) and full‐electron (FE) calculations for MoS 4 −2 , MoO 4 −2 , and MoOCl 4 compounds were analyzed. Geometry parameters, binding energies, charge distributions, and topological properties of the electronic density were studied for MoL bonds (L = S, O, Cl). Results clearly indicate that those approaches that include valence plus 4 s and 4 p electrons (ECP2 methods) are able to reproduce the topological properties of MoL bonds, charge distributions, and geometries with respect to those obtained by FE methods. ECP methods that consider only the 4 d and 5 s valence electrons (ECP1) fail in the calculation of molecular properties. The use of 5 p functions in ECP1 approaches produces a negative Mulliken charge on Mo. Bader's charges give more consistent results than Mulliken's ones. A new parameter for measuring the degree of ionicity is proposed. © 1994 by John Wiley & Sons, Inc.